SMP systems that provide separate caches for each processor introduce additional issues that affect application performance. Memory caches must maintain a consistent view of memory for all processors. This is accomplished by dividing up memory into small chunks (called a cache line) and tracking the state of each chunk that is present in one of the caches. In order to update a cache line, a processor must first gain exclusive access to it by invalidating all other copies in other processor's caches. Once the processor has exclusive access to the cache line, it may safely update it. If the same cache line is being continuously updated from many different processors, the cache line will bounce from one processor's cache to another. Since the processor cannot complete the write instruction until its cache acquires exclusive access to the cache line, it must stall. This behavior is called cache sloshing, since the cache line "sloshes" from one processor's cache to another.

The only way to deal with this problem is to not let it happen in the first place. A number of possibilities are being considered. One way, suggested by Roland, is to create a __dma_buffer attribute which can be used in the declaration of small buffers; on non-cache-coherent systems, this attribute would force the size and alignment of the buffer such that it would not share cache lines with any other data. Another approach is to require that all DMA buffers be allocated separately; the kernel memory allocation primitives already ensure that even the smallest buffers are properly aligned and padded. Yet another approach could be to simply disable caching for the page(s) in question while the operation is in progress; most architectures support this in their page tables. This approach could create performance problems, however (if the page in question has heavily-used data), and it could be complex.

David Miller, who wrote much of the current DMA code, has a different approach. He thinks that this kind of subtle cache issue is a trap for driver writers that should be simply avoided altogether. Rather than come up with new ways of working around incoherent caches, it's better to just change the rules and tell driver writers to allocate their small DMA buffers using the "PCI pool" interface. This interface, which was added in 2.4.4, was designed for just this purpose: allocating small buffers for DMA. Rather than make driver writers deal with this sort of cache coherence issue - and watch some of them get it wrong, David would bury it in the PCI pool code. While no real resolution has been proclaimed, this last option appears to be the likely outcome.

Cache thrashing occurs when two or more data items that are frequently needed by the program both map to the same cache address. Each time one of the items is encached, it overwrites another needed item, causing cache misses and impairing data reuse.

Study of 13,000 children exposes link between use of handsets and later behavioural problemsBy Geoffrey Lean, Environment EditorSunday, 18 May 2008

Women who use mobile phones when pregnant are more likely to give birth to children with behavioural problems, according to authoritative research.

A giant study, which surveyed more than 13,000 children, found that using the handsets just two or three times a day was enough to raise the risk of their babies developing hyperactivity and difficulties with conduct, emotions and relationships by the time they reached school age. And it adds that the likelihood is even greater if the children themselves used the phones before the age of seven.

The results of the study, the first of its kind, have taken the top scientists who conducted it by surprise. But they follow warnings against both pregnant women and children using mobiles by the official Russian radiation watchdog body, which believes that the peril they pose "is not much lower than the risk to children's health from tobacco or alcohol".

The research – at the universities of California, Los Angeles (UCLA) and Aarhus, Denmark – is to be published in the July issue of the journal Epidemiology and will carry particular weight because one of its authors has been sceptical that mobile phones pose a risk to health.

UCLA's Professor Leeka Kheifets – who serves on a key committee of the International Commission on Non-Ionizing Radiation Protection, the body that sets the guidelines for exposure to mobile phones – wrote three and a half years ago that the results of studies on people who used them "to date give no consistent evidence of a causal relationship between exposure to radiofrequency fields and any adverse health effect".

The scientists questioned the mothers of 13,159 children born in Denmark in the late 1990s about their use of the phones in pregnancy, and their children's use of them and behaviour up to the age of seven. As they gave birth before mobiles became universal, about half of the mothers had used them infrequently or not at all, enabling comparisons to be made.

They found that mothers who did use the handsets were 54 per cent more likely to have children with behavioural problems and that the likelihood increased with the amount of potential exposure to the radiation. And when the children also later used the phones they were, overall, 80 per cent more likely to suffer from difficulties with behaviour. They were 25 per cent more at risk from emotional problems, 34 per cent more likely to suffer from difficulties relating to their peers, 35 per cent more likely to be hyperactive, and 49 per cent more prone to problems with conduct.

The scientists say that the results were "unexpected", and that they knew of no biological mechanisms that could cause them. But when they tried to explain them by accounting for other possible causes – such as smoking during pregnancy, family psychiatric history or socio-economic status – they found that, far from disappearing, the association with mobile phone use got even stronger.

They add that there might be other possible explanations that they did not examine – such as that mothers who used the phones frequently might pay less attention to their children – and stress that the results "should be interpreted with caution" and checked by further studies. But they conclude that "if they are real they would have major public health implications".

Professor Sam Milham, of the blue-chip Mount Sinai School of Medicine in New York, and the University of Washington School of Public Health – one of the pioneers of research in the field – said last week that he had no doubt that the results were real. He pointed out that recent Canadian research on pregnant rats exposed to similar radiation had found structural changes in their offspring's brains.

The Russian National Committee on Non-Ionizing Radiation Protection says that use of the phones by both pregnant women and children should be "limited". It concludes that children who talk on the handsets are likely to suffer from "disruption of memory, decline of attention, diminishing learning and cognitive abilities, increased irritability" in the short term, and that longer-term hazards include "depressive syndrome" and "degeneration of the nervous structures of the brain".

Prenatal and Postnatal Exposure to Cell Phone Use and Behavioral Problems in Children.

This has been tested onWindows XP Pro Final and SP1 (Not home, but it should work fine)Windows 2003 Enterprise Server 3700RTMThe Free Evaluation version (Any 2k3 version should work fine)Windows 2000 Pro

If you can not delete a folder, just delete the files inside

C:\Windows and C:\Program Files assumed.

1. c:\windows\system32\dllcache\*

NOTE: DON’T DELETE THIS FOLDER, JUST ALL THE FILES INSIDE! This folder uses a LOT of hard drive space, it holds a backup of every system file that windows uses. Deleting this will cause a SFC error when you replace a system file instead of windows putting back the original file. For people who want to mod there system, this is a good thing.

2. c:\windows\servicepackfiles\i386\*

NOTE: DON’T DELETE THIS FOLDER, JUST ALL THE FILES INSIDE! This folder only exists if you installed a service pack on XP, if you did a slipstream it won’t be here either. This folder is the same as the dllcache, but has the new files that were updated by a service pack. If you delete the dllcache, deleting this is just like finishing the job.

3. c:\windows\$Uninstall----$

These $uninstall----$ folders are used whenever you want to uninstall a windows update. If you delete them, you can not uninstall the update(s), but if the updates are working fine for you, there should be now reason to remove them.

4. c:\windows\cursors\

This folder contains some custom cursers for windows, if you are happy with the default cursers, or use your own set like Blue Curve, then deleting this wont effect you at all.

5. c:\windows\driver cache\i386\

NOTE: DON’T DELETE THIS FOLDER, JUST ALL THE FILES INSIDE! This is one you may not want to delete, this takes up a bit of space (about 80mb) but windows uses if you ever add or remove windows components and things like printer drivers. If you’re your hardware is already working fine, you don’t need this folder on your hard drive. For example, if you delete this folder, and try to install IIS, windows will ask for the CD or Network share with the files on it, if you don’t need to add or remove windows components often, deleting this will free up some space for you.

6. c:\windows\help\

NOTE: DON’T DELETE THIS FOLDER, JUST ALL THE FILES IN SIDE! This folder contains all of the windows help files. If you are like me, and think they having 50mb of help files is a waste, then you probably want to delete it. If you delete this folder and try to view a help file, the Help and Support center will come up with a 404 error. No harm is done, you just can’t view the help files (because you deleted them…). There is also a tours folder inside of the help folder, you can delete everything in this folder also, but windows won’t let you remove the actual folder.

7. c:\windows\inf\

NOTE: DON’T DELETE THIS FOLDER, JUST ALL THE FILES INSIDE! This folder contains a lot of windows drivers, if you ever add new hardware, windows looks in this folder, then on your CD drive for the latest drivers. Any hardware you might get will probably come with the drivers on a disk, so this folder is just a wasting space on your hard drive with outdated drivers. If all of your hardware is working fine, and you don’t plan on adding any new hardware for a while, deleting this wont effect your system at all. If you don’t want to delete everything in it, you can go into the folder, press CRTL+F and search for mdm*.* and delete everything that comes up. These are all modem drivers, and it is very unlikely you will ever need them because you either have a modem installed already, or if you do add one, it will come with newer drivers.

8. c:\windows\srchasst

This folder is the XP Search assistant, if you delete it, windows will just use the classic 2k style search instead, which is more functional and easier to use.

WARNING: Some people have reported problems with this, and have not been able to search, try this at your own risk!!!

9. c:\windows\downloaded installations\

This folder holds the installers for some programs you download and install, for example, Tweak UI puts its installer in this folder, and so you can repair it or update its components later. Deleting this folder won’t harm any programs I have ever seen, but you should look inside this and see what you are deleting first.

10. c:\windows\media\

These are the default windows sounds, if you don’t want them, deleting them wont hurt anything.

11. c:\windows\system32\restore\

This is the system restore apps, if you delete this, system restore will no longer work. Before you delete this, you should go into System Restore, and delete all your restore points, and then you should go to the system properties and disable system restore. After that, you can delete this folder, and not worry about system restore slowing down your system or sucking up space.

12. c:\windows\system32\usmt\

This folder is the File and Settings Transfer wizard. If you have no need for it, then deleting this wont have any other effects besides the File and Settings Transfer wizard not working anymore.

13 A. c:\program files\msn13 B. c:\program files\netmeeting\

These are the MSN Explorer and Net Meeting applications. If you don’t need or use them, then you can delete these folders (For net meeting, you can only delete the files inside) and the only thing it will effect is that these programs will know longer work.

14. C:\windows\system32\oobe

NOTE: DON’T DELETE THIS FOLDER, JUST ALL THE FILES INSIDE! In this folder is the Out of Box Experience (The screens you see right after you have installed XP for the first time), and the XP Product Activation stuff. If you have a Retail or OEM version of XP, and you think you might ever need to activate again, DON’T DELETE THIS. So unless you are using XP or 2k3 CORP, you may still need this folder someday.

15. c:\windows\msagent

This folder holds the MS Agent program. The MS Agent is a gay little wizard thing that looks like the Office Assistant, I personally hate this thing, and removing it will get rid of it for good! If windows wont let you remove the folder, just delete everything inside of it, and everything inside of the intl folder.

16. c:\windows\java

This is the crappy MS Java components that don’t work well, and MS got sued over. If you have Windows XP slipstreamed with SP1a you wont have this because MS no longer distributes it. If you use websites that use Java Applets, you should keep this, or remove it and install Suns Java VM.

17. c:\windows\mui

This is a little app that allows you to switch between multiple languages, if you only use one language, then deleting this wont effect you at all. NOTE: I think this folder only exists on XP Pro because Home Edition doesn’t support multiple languages.

Post Deletion:

After you have deleted everything you want to, I recommend you run the Regisrty Cleaner from jvPowerTools ( http://www.vtoy.fi/jv16 ). This will remove all the references to things you deleted so a window doesn’t look for the files any more. If you delete the Java Folder, RegCleaner will find at least 50 reg entries related to it, and can remove them for you if you want.

What else can I do to make the windows folder smaller?

If you want to make your windows folder even smaller, and you use NTFS, you can use NTFS compression to make the windows folder smaller. Although you can compress everything it, compressing EXEs and DLL files will make you system a little bit slower, so I recommend compressing everything BUT EXE and DLL files.

Using this guide, you should easily be able to make your windows folder less then 1gb, but because some programs add there own files to the windows dir, your results may differ from what other people have gotten there folder sizes to. After a clean install, it is fairly easy to get your windows folder less then 700mb so you can put a image file of your clean install on one CD and be able to restore it easily.

That is all for now, if you have your own, feel free to post them below and if my system still works well after deleting them, I will add them to this guide!

The ext3 filesystem provides more journaling which makes it "safer" and recovery of files in case of a crash is more likely. This has its price in performance thou.ReiserFS is a faster filesystem but with less safety.

Ext3 & ReiserFS has three kinds of journaling methods:

Journal Data Writeback

Journal Data Ordered

Journal Data

the difference of the three is when the actual data is written to the filesystem in relation to the metadata and its entrance into the journal.

By default the the 2nd method is used.

To speed things up we will make it use method 1. price: old data might appear in files after a crash and journal recovery. The last things you wrote or did prior a crash isn't recovered.

Make ext3 or reiserfs use journal data writebackEdit /etc/fstab, Add the following line

(There have been reports of problems when rebooting if the following is not done)Note! tune2fs only works for ext3. Reiserfs can't change the journal method on the fly.Before rebooting change the filesystem manually to writeback.

Code:

sudo tune2fs -o journal_data_writeback /dev/hda1

Check that it is running

Code:

sudo tune2fs -l /dev/hda1

Remove update of access time for filesAccording to the manual the only thing that might happen if you turn this off is that when compiling certain things the make might need that info.

The problem of incrementing eth#This happens because somehow the MAC address is reported to linux in reverse.To fix this do the following :(i) dmesg | grep Macthis gives the mac address in reverse ( a line with Invalid Mac ...)note that down. that is the mac address in reverse

(ii) sudo nano /etc/udev/rules.d/70-persistent-net.rulesdelete any line that ends with NAME="eth#"add the following lineSUBSYSTEM=="net", DRIVERS=="forcedeth", NAME="eth0"now save the file

my first time to try VMware and it shut down?it is 08:50 am in TPE and 3am PDT=3+15=23 in TPECST, which means I have to wait til 23:00....damn...080702Ubuntu 8.0.4, Linux-2.6.24-17-generictar xf VMware-server-1.0.5-80187.tar.gzcd vmware-server-distrib./vmware-install.pl

For more information on how to troubleshoot module-related problems, pleasevisit our Web site at "http://www.vmware.com/download/modules/modules.html" and"http://www.vmware.com/support/reference/linux/prebuilt_modules_linux.html".

Execution aborted.

換到VMware-server-1.0.6-91891就好了Starting VMware services:Virtual machine monitor doneVirtual ethernet doneBridged networking on /dev/vmnet0 doneHost-only networking on /dev/vmnet1 (background) doneHost-only networking on /dev/vmnet8 (background) doneNAT service on /dev/vmnet8 doneremote console connection port [902]virtual machine files in [/var/lib/vmware/Virtual Machines]# vmware/usr/lib/vmware/bin/vmware: /usr/lib/vmware/lib/libgcc_s.so.1/libgcc_s.so.1: version `GCC_3.4' not found (required by /usr/lib/libcairo.so.2)/usr/lib/vmware/bin/vmware: /usr/lib/vmware/lib/libgcc_s.so.1/libgcc_s.so.1: version `GCC_4.2.0' not found (required by /usr/lib/libstdc++.so.6)/usr/lib/vmware/bin/vmware: /usr/lib/vmware/lib/libgcc_s.so.1/libgcc_s.so.1: version `GCC_3.4' not found (required by /usr/lib/libcairo.so.2)/usr/lib/vmware/bin/vmware: /usr/lib/vmware/lib/libgcc_s.so.1/libgcc_s.so.1: version `GCC_4.2.0' not found (required by /usr/lib/libstdc++.so.6)/usr/lib/vmware/bin/vmware: /usr/lib/vmware/lib/libgcc_s.so.1/libgcc_s.so.1: version `GCC_3.4' not found (required by /usr/lib/libcairo.so.2)/usr/lib/vmware/bin/vmware: /usr/lib/vmware/lib/libgcc_s.so.1/libgcc_s.so.1: version `GCC_4.2.0' not found (required by /usr/lib/libstdc++.so.6)

I had the same problem and fixed it like thisI copied/usr/lib/libpng12.so.0to/usr/lib/vmware-server-console/lib/libpng12.so.0/and/usr/lib/gcc/i486-linux-gnu/3.4.6/libgcc_s.soto/usr/lib/vmware-server-console/lib/libgcc_s.so.1/libgcc_s.so.1it seems that the libraries shipped with the vmware server do have problems with the cairo library (no version given ??).

Complete InstallationA complete installation installs the utilities to enhance the performance of the guest operating system, and all the drivers  the VMware SVGA driver, the VMware Mouse driver, the VMware SCSI driver, the VMware vmxnet networking driver (the vlance driver is installed automatically when you created the virtual machine) and the shared folders driver (for use by virtual machines with VMware Workstation).

The Plastic ProblemMost bottled water comes in polyethylene terephthalate bottles, indicated by a number 1, PET or PETE on the bottle's bottom. (No, it's not the same phthalate mentioned earlier.) The bottles are generally safe, says Ken Smith, PhD, immediate past chair of the American Chemical Society's division of environmental chemistry. But scientists say when stored in hot or warm temperatures, the plastic may leach chemicals into the water.

(.................................)

In the meantime, experts have raised a warning flag about a few specific chemicals. Antimony(銻) is a potentially toxic material used in making PET. Last year, scientists in Germany found that the longer a bottle of water sits around (in a store, in your home), the more antimony it develops. High concentrations of antimony can cause nausea, vomiting and diarrhea. In the study, levels found were below those set as safe by the EPA, but it's a topic that needs more research.

Last summer, a National Institutes of Health (NIH) committee agreed that bisphenol A (BPA)(雙酚甲烷A), a chemical found in polycarbonate(聚碳酸酯, PC) (used to make watercooler jugs, sport-water bottles and other hard plastics, but not PET), may cause neurological and behavioral problems in fetuses(胎兒), babies and kids. A separate NIH-sponsored panel found that the risk was even greater, saying that adult exposure to BPA likely affects the brain, the female reproductive system and the immune system. The FDA has reviewed these reports and says it will keep monitoring the data to see if the agency needs to take regulatory action.

你就會看到./include/linux/netfilter/xt_limit.h:18: /* Ugly, ugly fucker. */./net/netfilter/nf_queue.c:171: /* James M doesn't say fuck enough. */./net/netfilter/xt_limit.c:5: * Alexey is a fucking genius?./net/ipv4/netfilter/ip_nat_snmp_basic.c:1032: * (And this is the fucking 'basic' method)../net/xfrm/xfrm_algo.c:687: /* Fuck, we are miserable poor guys... */./sound/oss/aci.c:160:/* The four ACI command types are fucked up. [-:./sound/oss/opl3.c:837: * What the fuck is going on here? We leave junk in the beginning./lib/vsprintf.c:9: * Wirzenius wrote this portably, Torvalds fucked it up :-)./fs/jffs/intrep.c:2996: don't fuck up. This is why we have./fs/binfmt_aout.c:325: /* Fuck me plenty... */./Documentation/DocBook/kernel-locking.tmpl:1375: If you don't see why, please stay the fuck away from my code../drivers/media/video/bt819.c:209: BUG? Why does turning the chroma comb on fuck up color?./drivers/mtd/mtd_blkdevs.c:370: registered, to prevent the link/init ordering from fucking./drivers/char/watchdog/shwdt.c:115: * brain-damage, it's managed to fuck things up one step further.../drivers/net/sunhme.c:1027:/* Only Sun can take such nice parts and fuck up the programming interface./drivers/net/sunhme.c:2100: /* This card is _fucking_ hot... */./drivers/net/b44.c:905: /* ??? What the fuck is the purpose of the interrupt mask./drivers/ide/pci/cmd640.c:16: * These chips are basically fucked by design, and getting this driver./drivers/scsi/esp.c:2570: * how bad the target and/or ESP fucks things up../drivers/scsi/esp.c:2659: * phase things. We don't want to fuck directly with./drivers/scsi/esp.c:3354: /* Be careful, we could really get fucked during synchronous./drivers/scsi/qlogicpti.h:64:/* Am I fucking pedantic or what? */./drivers/scsi/NCR53C9x.c:1763: * how bad the target and/or ESP fucks things up../drivers/scsi/NCR53C9x.c:2689: /* Be careful, we could really get fucked during synchronous

You don't say if you ported OCF from sf.net, or from the OCF git treeon http://hifn.xelerance.com/

The latter is based upon 2.6.18 kernel, so perhaps not.

There have been numerous improvements in the past 4 months to OCF, butwe are still not seeing multiple packets being submitted to the hardwaredriver layer from OCF. As such, the hardware's pipeline is not beingkept full.

Since April 2006, Xelerance has been hard under contract with Hifn to provide support in Linux and FreeBSD for the Hifn product line. {Likely, it will eventually work on NetBSD, and OSX too}

We are finally putting the finishing touches on code that has slowly evolved. We have been trying to move our kernel component into a state where it could deal with doing asynchronous symmetric cryptography operations. Similarly, in userland we want to support doing asynchronous asymmetric public key operations. Being able to do this means being able to offload these things to hardware.

We are pleased to announce a 3.0.00 release. It includes offload of both symmetric and assymetric operations.

Wii modchips have been around since the start of the year in one form or another,but some folks at the 24th Annual Chaos Communication Congress just demoed a new Wii hack that lets them have full access to the console,including all the hardware. By using a custom serial interface, they were able to grab access to the encryption and decryption keys during runtime by doing memory dumps. Don't worry about the details if you'renot sure what's going on, just know that you're going to be able to run even better homebrew and "backup" Wii games in the near future.